[1] Univ Basel, Biozentrum, Basel, Switzerland
[2] Univ Autonoma Madrid, Dept Biol Mol, Madrid, Spain
[3] Univ Autonoma Madrid, Ctr Biol Mol Severo Ochoa, Madrid, Spain
[4] Univ Lausanne, Ctr Integrat Genom, Lausanne, Switzerland
[5] Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA
[6] Univ Minnesota, Sch Med, Dept Biomed Sci, Duluth, MN 55812 USA